A deficiency of many current septic tank waste water filter designs is the difficulty that arises in servicing the filters. Many waste water filter designs include filter cartridges or elements which are disposed within a housing or shield. Unfiltered waste water enters the shield at inlet locations and must pass through the filter element to proceed to an outlet. In other waste water filter designs, the housing or shield includes apertures or other inlet openings that are sized to restrict the entry of solids that are larger than the openings. In these filter designs, the apertures or inlet openings provide a first filter through which the waste water must pass before advancing through the filter element within the housing and proceeding to the outlet.
In many filter designs, removal of the filter element for servicing leaves the outlet exposed to unfiltered or inadequately filtered waste water. Such filter element removal is periodically required in many waste water filters, particularly in filters not providing self cleaning characteristics, to remove accumulated solids on the filter surfaces and within the housing.
As there is no provision in these filters to restrict the entry of waste water into the filter housing or shield, unfiltered or inadequately filtered waste water will pass unobstructed to the outlet. There are several detrimental effects caused by the passage of unfiltered or inadequately filtered waste water to downstream waste water components as well as to groundwater resources. These detrimental effects are in many cases severe and exist for waste water filters which are gravity flow as well as those which utilize a pump.
In gravity flow filters, solids passing unobstructed through the filter housing to the outlet may accumulate in the modulating orifices in the filter as well as in the outlet pipes causing lower operational efficiencies or blockages. Similar decreases in efficiencies as well as blockages will also occur in sand filters and drain fields as solids accumulate in these waste water system components.
In filters utilizing pumps, unfiltered waste water or inadequately filtered waste water passing unobstructed through the filter housing would enter an outlet reservoir or pump inducer either within the housing or shield or attached to it. These solids may plug and possibly destroy a pump once the pump is activated. Solids which do not plug the pump will be discharged to downstream waste water system components with previously described detrimental effects. In some waste water filters of this type, the outlet opening that feeds the outlet reservoir or pump inducer is beneath the bottom of the filter element. As the filter element is reinstalled after cleaning, the filter element serves to trap solids that have entered into the shield interior at the bottom of the housing or shield. Or, the reinstallation of the filter element will push these solids directly into the outlet reservoir or pump inducer. These solids, having no other exit, will be discharged from the filter through the pump. These solids are responsible for significant damage to pumps as well as causing the previously described problems to downstream system components and downstream water sources.
In some filter designs, particularly filter designs having pump inducers which are attached to the housing or shield, the pump may be allowed to operate while the filter element is removed. In these designs, a large amount of solids could actually be discharged while servicing of the filter element is occurring, if the service technician has not deactivated the pump.
If servicing the filter element requires the deactivation or removal of the pump, solids that have entered into the shield or housing will still be allowed in many instances to pass unobstructed to the pump chamber while the filter element is removed. These solids may accumulate within the shield or pump chamber and be subsequently discharged through the pump causing similar problems to the pump and down stream waste water system components.
Another problem associated with the discharge of unfiltered solids is that undigested solids containing biological hazards would be included within the solids that are inadvertently discharged. These undigested solids pose substantial health threats and have been responsible for illnesses in humans as well as the degradation of wildlife habitat. Accordingly, most waste water regulations are drawn to the discharge of undigested solids.
For the foregoing reasons there is a need for a waste water filter that includes easily removable filter elements that allow for the easy servicing of the waste water filter elements. In these waste water filters there is a need for either ensuring that unfiltered or inadequately filtered waste water will not be discharged from the filter during the servicing of the filter element or restricting the discharge of unfiltered or inadequately filtered waste water. In waste water filters utilizing pumps there is a need that unfiltered or inadequately filtered waste water will not be allowed to enter a pump chamber, or be restricted from entering the pump chamber, while the filter element is removed for servicing or be restricted from entering the pump. This ensures that solids which are known to damage pump components will not be passed through the pump upon activation of the pump.
There is yet another need for a waste water filter that protects downstream waste water treatment system components such as pipes, sand filters, drain fields, and lagoons from inadvertently discharged solids which may accumulate within these components causing decreased operational efficiencies and blockages. There is a further need for a waste water filter that protects ground water supplies from the inadvertent discharge of undigested solids which pose a health hazard to humans and wildlife.
There are also significant deficiencies associated with the filter elements used within current septic tank waste water filter designs.
A first deficiency in existing filter elements is the lack of self cleaning characteristics. Many existing waste water filter elements require the use of a closed bottom shield. In these filters, waste water solids that enter the shield inlet openings have no exit and will accumulate within the shield. Other existing waste water filters use an open bottomed shield which encloses a filter element having multiple stacked disk dam filter sections. The accumulation of solids in these filters is on horizontal surfaces which retain the solids until the element is removed for cleaning. There is no provision for self cleaning in either of these filter designs. Solids will accumulate within the filter during the filtering of waste water. These solids will remain within the filter until they degrade or are removed during a cleaning process. The presence of accumulated solids within the filter results in a decrease in filter efficiency. In many cases, the cleaning will not be performed until plugging is detected.
A second deficiency of existing filters is the difficulty encountered in removing the filter element for cleaning or replacement.
Many existing filters do not allow for the easy removal of the filter element from the shield, and require the entire waste water filter to be removed from the septic tank so that the filter surface or filter element can be cleaned. These filter designs may accumulate a large quantity of solids within the filter. These solids along with the waste water within the filter require the person servicing the filter to lift a substantial amount of weight when removing the filter from the septic tank.
Some existing filters may also restrict the removal process by disposing float switches, pumps, and piping within the interior of the filter element. These filter components must be removed from the element interior before the element can be removed from the shield. Removal of pumps and piping may require the difficult disassembly of threaded fittings.
Another deficiency of previous filter designs is a result of the manner that waste water is supplied to the filter. In either design there is essentially a single route or flow pattern for waste water to proceed into the housing and through the filter. In the past filter designs utilizing a single filter surface, waste water is able to enter the housing at various openings all of which advance the waste water to the same location within the housing and provide the waste water with a single surface such as a screen through which the waste water must pass to be discharged from the tank by a suitable means. In past filter designs using multiple filtering tubes, waste water enters the housing at various openings which are disposed at one or two vertical positions on the housing, which allows the plugging of multiple openings at the same time. Similarly, in the past filter designs utilizing multiple stacked filter elements, waste water enters the housing only at a single location and is then able to proceed through the filter. If the filter surface or filter elements of either system clog, no alternative flow pattern is possible to pass water through the filter. Furthermore, if the single inlet opening of the housing becomes clogged by the eventual upward advancement of the sludge layer or by the eventual downward movement of the scum layer the housing will not provide an alternative flow pattern for the waste water to access the filter.
Yet another deficiency of existing filters is the inability of these filters to provide sequential filtering. In particular, there are few filters which use multiple filter surfaces having a series of progressively smaller filter openings through which the waste water must pass. Sequential filtering is not possible with most existing filters which are of a design having a single filter surface. Because of the single filter surface limitation, there is typically no ability of the filter to remove small solid waste particles from the waste water, as a single filtering surface with small filtering openings would quickly plug.
For the foregoing reasons there is a need for filter elements which provide self cleaning characteristics to the waste water filters in which the filter elements may be used. There is a further need for filter elements which are easily removed for cleaning, as well as a need for filters which allow for the proper placement of pumps and pump switches so that pump removal will typically not be required for filter element servicing. There is yet a further need for filter elements which provide alternative flow patterns, as well as a need for filters which provide sequential filtering.
The waste water filter of the present invention satisfies the previously mentioned needs for a waste water filter.
The waste water filter of the present invention comprises a shield comprising a vertical peripheral wall defining a shield interior. The shield further comprises an inlet for the entry of unfiltered wastewater into the shield interior. A shield filter element is disposed within the shield interior. An outlet in fluid communication with the filtered waste water within the shield interior for discharging filtered waste water is also included into the waste water filter.
The shield filter element includes at least one filter surface having filter surface openings for the passage of relatively clear water while restricting the passage of solids larger than the openings. The shield filter element, when disposed within the shield, separates the shield interior into first and second interior locations. Unfiltered or partially filtered waste water in the first interior location is separated from filtered waste water in the second location by the shield filter element. The shield filter element is removable from the shield. Unfiltered or partially filtered waste water entering the shield interior after shield filter element removal will enter the first and second interior locations within the shield.
The waste water filter further includes means for preventing the flow of unfiltered or partially filtered waste water from the shield interior from passing through the outlet after the removal of the filter element from the shield.
The means for preventing the flow of unfiltered or partially filtered waste water from the shield interior through the outlet, may comprise an outlet filter which separates the shield interior from the outlet. The outlet filter is typically disposed within the waste water filter independent of the shield filter element. The outlet filter may include filter openings of a larger size than the smallest sized openings of the shield filter element filter surface. The outlet filter may also be included in a waste water filter including a shield filter element which includes a series of filter surfaces through which waste water must pass. The filter openings of the outlet filter in this version would typically be equal to or larger than the last openings of the shield filter element through which the waste water passes before passing through the outlet filter.
The means for preventing the flow of unfiltered or partially filtered waste water from the shield interior from passing through the outlet after the removal of the filter element from the shield may also comprise a gate valve.
The means for preventing the flow of unfiltered or partially filtered waste water from the shield interior from passing through the outlet after the removal of the filter element from the shield may be removable from the waste water filter.
The waste water filter may further include an outlet reservoir disposed intermediate the outlet filter and the outlet. The means for preventing the flow of unfiltered waste water from the shield interior from passing through the outlet after the removal of the filter element from the shield may be removably disposed within the outlet reservoir.
The outlet reservoir may include a vertical peripheral wall which is directly attached to the vertical peripheral wall of the shield. The vertical peripheral wall of the shield may also be partially disposed within the vertical peripheral wall of the outlet reservoir. The outlet reservoir typically includes a discharging means such as a pump.
In another version of the invention, the shield includes an inlet comprising filtering apertures which partially filter the waste water entering into the shield before the waste water passes through the filter element. In this version, an outlet filter or gate valve is used to ensure that solids within the partially filtered waste water do not pass out the filter to the outlet. An outlet filter allows the passage of filtered waste water to the outlet. A gate valve prohibits the passage of any partially filtered waste water to the outlet.
In another version of the invention, the outlet protection is not accomplished by an outlet filter but is provided by the proper placement of the inlet openings which feed waste water to an outlet reservoir. In these waste water filter designs, the inlet opening is placed at a location on the peripheral walls of the shield and outlet reservoir so that a seal on the filter element will force unfiltered waste water away from the opening and either through the filter element or out the filter shield entirely during filter element reinstallation.
The outlet protection provided by this outlet opening location is not as extensive as that provided by outlet filters or valves. However, the design does ensure that a minimum of waste water solids that enter the shield during filter element removal will enter the outlet reservoir to be discharged out the filter.
The present invention provides benefits which previously have not been available in waste water filters.
The use within the present invention of either an additional outlet filter surface, a gate valve, or a properly positioned inlet opening to an outlet reservoir ensures that unfiltered or inadequately filtered solid waste particles, as well as undigested solid waste particles will not be discharged from the filter to downstream waste water system components while the filter cartridge is removed for servicing.
Accordingly, the waste water filter of the present invention ensures that during the period the filter element is removed or as a result of previous filter element removal, the downstream components of a pump, pump vault, outlet lines, sand filter lines, sand filter bed, lagoon or drain field will not be subject to the plugging effect of unfiltered or inadequately filtered solid waste particles.
The present invention also ensures that undigested biological wastes will not be discharged that may eventually enter ground water sources threatening human water supplies as well as wildlife habitat.
The present invention also provides significant benefits to filter elements used in waste water filters.
The present invention addresses the need for a waste water filter to be self cleaning. The waste water filter of the present invention utilizes a shield and filter arrangement wherein the shield is typically constructed with essentially an open bottom. As particles are dislodged from the filter surfaces by the somewhat turbulent flow within the filter the particles are permitted to precipitate out of the first and second interior locations and out the bottomless shield, as well. These particles will then precipitate to the sludge layer at the bottom of the tank. Similarly, solid waste particles that have entered the first and second interior locations and have been digested by biologically active agents in these same locations will also be permitted to exit the shield and precipitate to the sludge layer. The obvious benefits of a self cleaning filter are decreased maintenance costs necessary to clean out or replace a clogged filter.
The present invention further satisfies the need for easy filter element removal. The waste water filter typically uses interchangeable filter elements that are easily installed and removed from the filter shield. The present filter design allows the removal of the filter cartridge by merely lifting upward on the element which extracts the element from the shield. Once removed, the element can be easily cleaned with out disassembly of the element. The filter system also allows for the easy replacement of a filter element should the element become damaged or if different filtering characteristics are desired. The waste water filters of the present invention present essentially no difficulty in positioning the filter elements within the shields of the filters. The filter elements can be inserted into the shield until the element abuts the filter element support surfaces within the shield.
The present invention further addresses the need for alternative flow patterns through the filter. The filter typically utilizes two filter surfaces each in fluid communication with a separate interior location within the shield. Both interior locations of the shield contain unfiltered waste water but are in direct fluid communication with each other. This arrangement essentially provides the filter with two flow through patterns within the filter and shield. The first flow pattern being waste water entering into the shield and passing into a first interior location and subsequently through the first filter surface into the interior of the filter. The second flow pattern being waste water entering into the shield and passing into a second interior location and subsequently through the second filter surface into the interior of the filter. This filter arrangement will be unlikely to clog due to the two flow through patterns as both flow through patterns would have to become blocked to restrict the operation of the filter.
This arrangement may also include the added benefit of having unfiltered waste water pass through filter surfaces which have been disposed at different heights. This alternative design allows the solids to first accumulate on the lowest filter surfaces. As the lower filter surfaces lose efficiency due to accumulated solids, the waste water flow through the filter will be transferred to higher filter surfaces. This concept may also prevent an abrupt plugging in the filter as the plugging must occur sequentially on the different height filter surfaces.
The present invention provides filter elements having multiple filter surfaces having progressively smaller openings which allows for a very high level of solids removal while maintaining filter efficiency. As only the largest solids will be filtered by the first filter surface, only the largest of the solid waste particles can accumulate on the first filter surface. Similarly, of the solid particles that are allowed to pass through the first filter surface, only the largest of these particles will be filtered by the second filter surface, and accordingly, only larger particles may accumulate on the second filter surface. For this reason, the use of sequential filter surfaces having progressively smaller filter openings restricts the accumulation of solids on each surface and allows for efficient filter operation while ensuring a higher level of solids removal than is currently available by existing filter designs.